Laminated core and method for the production of a high permeability soft magnetic alloy

Abstract

A soft magnetic alloy is provided. The alloy consists essentially of 5 wt %≤Co≤25 wt %, 0.3 wt %≤V≤5.0 wt %, 0 wt %≤Cr≤3.0 wt %, 0 wt %≤Si≤3.0 wt %, 0 wt %≤Mn≤3.0 wt %, 0 wt %≤Al≤3.0 wt %, 0 wt %≤Ta≤0.5 wt %, 0 wt %≤Ni≤0.5 wt %, 0 wt %≤Mo≤0.5 wt %, 0 wt %≤Cu≤0.2 wt %, 0 wt %≤Nb≤0.25 wt % and up to 0.2 wt % impurities.

Description

[0001]This U.S. patent application claims the benefit of DE Patent Application No. 10 2019 110 872.1, filed on Apr. 26, 2019, the entire contents of which are incorporated herein by reference for all purposes.BACKGROUND1. Technical Field[0002]The present invention relates to a laminated core and a method for the production of a soft magnetic alloy, in particular a high permeability soft magnetic alloy and a laminated core.2. Related Art[0003]Non-grain-oriented electrical steel with approx. 3 wt % silicon (SiFe) is the most common crystalline soft magnetic material used in laminated cores in electric machines. As the electric-powered vehicle sector progresses, more efficient materials that perform better than SiFe are needed. In addition to sufficiently high electrical resistance, this means that a higher level of induction, in particular, is desirable to provide high torques and / or compact components.[0004]Even more efficient materials are desirable for use in sectors such as the au...

AI Technical Summary

Benefits of technology

The patent describes a method for controlling the cooling rate of sheets made from a specific material. The cooling rate should be between 10 to 50 K / h, preferably between 10 to 300 K / h, to achieve good soft magnetic properties and eliminate the need for separate annealing or maintenance. A faster cooling rate can also be used to improve soft magnetic properties, but it should be slower than 10 K / h to maintain flatness of the sheets.

Problems solved by technology

It has been found that heating or cooling sheets too quickly results in wavy sheets that also exhibit a type of plastic deformation within the sheets.

This leads to a contraction of the sheets.

This is undesirable in some applications such as laminated cores.

As a result, in this embodiment during heat treatment the sheets do not yet have their final shape and may be rectangular.

Quenching is a difficult process to control, particularly where large quantities of materials are concerned, as it is hard to achieve sufficiently fast cooling rates and ordering may therefore take place, with the resulting embrittlement of the alloy.

If annealing takes place in the two-phase region or in the FCC region, remnants of the FCC phase may impair the magnetic properties after cooling and incomplete retransformation.

Even if retransformation is complete, the additional grain boundaries created still have an damaging effect since coercive field strength behaves inversely proportionately to grain diameter.

45,000 J / m3 at 17 wt % Co), the potential for particularly good soft magnetic properties in these FeCo alloys is limited.

4,000 and its application is therefore limited, particularly in terms of motor and generator applications.

Annealing at such high temperatures is not conceivable with the FeCo alloys known to date.

As a result, the original flatness of the sheets is not maintained and the fill factor of the laminated core is reduced.

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